Twelve-year-old Sam lives in Pascagoula, Mississippi, where his family moved after his father became the city's chief of police. Sam is reeling from a brutal beating he and his only friend, Grover Middleton, the son of a wealthy surgeon, suffered at school when two older boys attacked them in front of the student body. Though the assailants were arrested, Sam cannot shake the humiliation. He blames Grover for making him a target and has been withdrawing while telling everyone he is fine.
When Sam receives a fishing skiff, the
Bream Chaser, for his birthday, he ventures alone into the Pascagoula River Delta, a vast uninhabited marsh his father has warned him against. His secret goal is to find the body of a missing man whose abandoned, blood-streaked jon boat was recently recovered. Deep in a waterway called Ware Bayou, he hits a submerged piling that nearly kills his engine, then spots a face watching him from a leaning cabin numbered 64.
The face belongs to Davey, a boy Sam's age who is barefoot, filthy, and nearly blind behind damaged glasses. He says the camp belonged to his family and that his brother arranged his return. His mother is dead. Sam promises to bring supplies.
Over the following days, Sam tells his parents he is fishing while secretly ferrying supplies to the camp. He helps Davey set up catfish jug lines and repair the rafters. Davey offers Sam thousands of dollars in cash from his brother Slade, but Sam refuses. Dad teaches Sam to replace a shear pin on the propeller, a skill that proves critical later. Dad also brings home Officer Jim Stockton, a marine police officer who asks Sam to watch for a jon boat linked to a fish market robbery, last seen heading toward Davey's camp.
Sam's friendship with Grover deteriorates. During a sleepover, he explodes at Grover, saying the beating might never have happened if they were not friends. Sam retreats to Davey's camp, which has become his emotional refuge.
A tropical storm strands Sam at home for two days. When it passes, he finds Davey shivering on the deck, barely responsive. The roof has partially blown off, and Davey is despondent because his family never came. He reveals that his father, John Wilcox, was sent to Parchman, the Mississippi state penitentiary, for stabbing his stepmother's boyfriend. Slade is Davey's stepbrother, who smuggled Davey out of a foster home where the foster father abused him and damaged his eyesight. Sam nurses Davey, helps replace the roof tin, and spends the night. They confide their fears to each other.
Sam wakes to Davey shouting that Slade has arrived. Slade, about 18, appears by boat with two friends, Jesse and Fred. He tells Davey their father "hasn't made it yet" and privately threatens Sam, revealing he knows Sam's home address from the boat's registration. The next morning, Slade takes the
Bream Chaser without permission and returns with the fuel tank nearly empty.
Sam tries to apologize to Grover, but the visit erupts into another argument. Soon after, Grover takes his Boston Whaler out alone and crashes into an abandoned dock. Officer Stockton finds him with a broken arm and broken ribs. That evening, Sam opens up to Dad, who tells him that being a man means helping people however you can. Sam visits Grover and apologizes. The two reconcile, and Grover urges Sam to return to the swamp and help Davey.
Sam returns one final time. The camp is deserted. Following a trail inland, he discovers a marijuana field Slade and his friends have been cultivating. Slade catches Sam and demands he transport drugs in the
Bream Chaser, threatening his life. When Davey reveals that Sam's father is a policeman, Slade becomes enraged. He beats Jesse for objecting, then tells Davey their father is not coming: Slade told the man where Davey was, and he never showed up. Slade confiscates the fuel hoses from both boats and takes Fred to harvest the crop.
Davey gives Sam a hidden fuel hose, then disappears into the swamp. Sam flees with Jesse, but he hits the same submerged piling, shearing the propeller pin. As they hide from Slade in the dark, they stumble over a decomposing body. By the light of Jesse's cigarette lighter, Sam sees a jagged scar on the dead man's forehead, matching Davey's description of his father. Davey's father came for his son but died in the swamp.
Sam refuses to fix the boat unless Jesse drops the backpack of stolen money. Jesse complies. Sam hangs the money on a branch for Slade to find, installs the spare shear pin his father taught him about, and sends Jesse away in the
Bream Chaser. He walks back through the dark swamp alone, determined to tell Davey the truth.
At the camp, Sam tells Davey about the body and the scar. Davey confronts Slade, saying, "You're going to leave me anyway," then leaps from the deck and flees. Slade leaves without him.
Sam pursues Davey through a flooded cypress pond in darkness. He finds Davey in chest-deep water, saying he has nobody left. Sam convinces him to keep going, and they swim through the night, taking turns holding a signal flare above water. At dawn they reach the Pascagoula River, but Slade's boat rounds the bend. Davey, nearly blind, refuses to slow Sam down. Slade drags Davey into the boat.
Moments later, Officer Stockton's patrol boat appears. Dad leaps out and embraces Sam. Stockton pursues Slade and blocks the river while Dad bluffs Slade with an unloaded AR-15. Slade swerves and crashes into the patrol vessel. He is handcuffed. Davey, ejected on impact, is found floating facedown. Stockton performs CPR, and Davey revives. Sam tells Dad and Stockton everything. Grover, who alerted Sam's parents about the swamp, calls to check on him.
Davey still needs a home. Mom uses her church connections to arrange foster placement interviews. Davey asks each couple about their dogs, testing how they treat those who depend on them, and rejects both families. Dad invites Stockton on a fishing trip with the boys. Stockton, who lost his young son to a brain tumor, bonds with Davey, quietly cleaning his glasses and sharing stories about his late dog. Davey offers to help Stockton pick out a new dog, and at an animal shelter, selects a black Lab-beagle mix. That night, he tells Stockton he wants to live with them.
Mom helps the Stocktons with adoption paperwork, and Davey moves in. The coroner determines his father died of a heart attack, and a graveside service is held with Stockton standing behind Davey, hands on his shoulders.
The night before a fishing trip to Horn Island with Grover, Sam and Davey camp on the dock. Davey urges Sam to tell Julia, the prettiest girl in class, that he thinks she is pretty. Sam reflects that the beating was not a lesson about winning fights but about being brave enough not to lose against yourself. When Davey says he cannot wait for tomorrow, Sam knows they have found the right people to face whatever lies ahead.